Lightning arrester



A ril 13 1926.

p R. E. MARBURY LIGHTNING ARRESTER Filed April '7, 1922.

WITNESSES:

INVENTOR fia 40h E. Narbu/ y.

ADTTORNEY l eased Apr. 13, 1926.

UNITED.) STATES .JP'ATENT OFFICE.

RALPH-E. IABBIIB E, OF WILIKINSBURG, PENNSYLVANIA, 'ASSIGNOR T0 WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CQBPOBATION OI PENNSYL- 'vnrn.

- L LIGHTNING. ARRESTER.

Application filed April 7, 192a Serial No. 550,215.

To all whom it may concern:

Be it known that 1,-RALPH E. M'ARBURY, a citizen of .the Unitedv States, and a resident of Wilkinsburg, in the county of Allegheny and-State of Pennsylvania, have invented a new and useful Improvement in Lightning Arresters, of which the following is a specification;

My inventlon relates to protective devices,'

more especially toa protective device emj-pldyed in conjunction with condensers toprotect them from abnormal voltages.

It is among the objects of this inventiorr to provide a protective device for condensers which shall be designed to break down at voltages that are inexcess of the normal -voltages for which the condenser is designed and which shall function to protect other devices included in the same circuit.

It is another object of this invention to provide a device of. the above designated type which shallbe of simplecom'pact struc-- mm, which shall be inexpensive and adapted to be readily manufactured in production quantities and which shall be readily accessible for renewals in case of breakdown in service.

Condensers employed in electric railways are connected between the line and the ground and are ordinarily designed for approximately double, the normal voltage; Occasionally, abnormal charges accumulate for a very short'timewhich breaks down the insulation of the condenser and leaves the electrical apparatus. unprotected until repaired; I

' My invention provides means for protect ing the .condenser element so that its opering a part hereof and-in which 1i ativefunction is undisturbed in the event of accumulation of excessive line voltage.

In the accompanying drawini constitut- Y characters designate likeparts,

Figure 1 is a diagrammatic, view of acondenser electrically connected. between "line and ground having a protective device connected therewith inaccordance with this invention;

t'ective device.

e reference Fig. 2 is a cross-sectional view, partially in elevation, of .a casmg embodying a condenser and a protective device;

3 is a' side elevational view of a speclal type of gap plug constituting one of the embodiments of this invention; and

nected between a line'2 and ground, 3, and

e I \1 0 a protectlve device, compris ng a gap element or plug 4 and aseries resistance rod 5, f

is shunted across the condenser 1 at 'the points 6 mm. The plug4 (Figs. 4.and 5) comprises a pair of sheet-metal discs 8 and 9 having a dielectric 10, preferably of a thin film of varnished silk therebetween to pro.- vide a. film cut out or gap.

Referring to'the Fig. 2, the condenser 1 is disposed within a suitable casing 11 having terminal bushings 12 mounted therein and connected to the terminals 13 ofthe condenser. The plug 4 is inserted through the condenser casing and islprovided with 1 a pair of spring clips 14 making contact with a pair of strips 15 connected to the terminals 12 through the. resistance rod 5. ,The ele 3 spring clips 14 to insure contact under pressure, thereby completing the shunt connection across the terminals 12. lamp 16 is shunted across part or the resistance 5 to .me'nt-s 8, .9 and 10 are inserted between the.

indicatethe operative condition of the pro-- The operation of the device is briefly as follows: The condenser 1 is connected to the The resistance plug 4Qand rod 5 is of such magnitude. that the current will pass 'from one terminal through the condenserto-the other terminal under normal conditions. On

surges, which occur -fre-' ed to small switchin quently', the mam condenser 1 is desi protect the; apparatus; If asud en abterminals 12 in a manner indicated in the 'ments 4 andl5,-respectively, shunted across devji'ceconnected in parallel to said condenser, saidcu't-Out beingproportionedto --plugh avmg-a pluralityof. metal discs and normal voltage accumulates on theline 2, causing a violent surge, the current will pass throughthe resistanceb. across the contacts 4 15 to the. plug land will break down the 5 film cut-out consisting of the varnishedsilk film between the metal discs 8 and 9, causing them to weld or fuse together, and short-circuiting the condenser 1. Practically all the current in the circuit 10 passes through the rod 5, thus notifying the operator that the plug li s short-circuited. The circuit is then broken by removing the trolley from the line and the plug 4 is then removed and replaced by a similar plug, having a new film element therein to again render'the' device-operative. The lamp 16, upon short-circuiting of the, lug 4, becomes lighted, owing to the current owing through rod 5, thus providing additional means for notifying the operator of failure of the plug device.

- It will be readily understood from the above description of my invention that a phrotective device formed in accordance erewith provides a simple and inexpensive.

means for protecting condensers employed in trolley-line service. This device is .relatively inexpensive, as compared with condensers, having suflicient insulation to withoccur in service. I v

Although I have describeda s ecific embodiment of my invention, it"will eobvious to those skilled in the art that various 86 chang'es'may be made in the details of con- -ao standabnormally high voltages that may 'struc'tion thereof; For instance,the condens- .ers and housing may be of any other suitable shape and construction, the lu may be of any, suitabl'econstfuction to 01 conducting 40 and dielectric materia'ls and may be connected in any "suitable manner to the resist, ance'and'terminalelements. The' lamp connected; in-the resistance circult' is not essential and maybe elimin'ated. These andother 4.6 changes may be made in the details of con struction of my'invention'without departing- 'irom .the principles: herein set forth. I claim'as 1n invention:

1'. The-{combmation with a ratus connccted to sai line, of an excessvoltage protective device therefor e'ompris inga condenserlconnected to saidjline,.zsaid condenser"being -of such capacity as'to limit eluding afilni' cut-out and a-current limiting break-down when the voltage across the ccndenserrises-abovea safe operating value; a, pairof s ring clips, said plu being held ibetween sai clips, a resistance 9 ement make.

2; Insemination with a condenser, s.

" 38 protective" device' comprising a removable p electric J jexposedito-excess volta e surges and appa-' a plurality, of metal discs an condenser heing of such capacity as to limit the voltage rise across said apparatus on normal switching surges or the like to a value below the breakdown voltages of the condenser insulation, a shunt circuit including a film cutout and a current limiting device connected in parallel to said condenser, said cutout being proportioned to break down and become short c rcuited at voltages corresponding to the breakdown voltageot said condenser, and an annunciator responsive to aflow of current in said shunt circuit.

4; An excess-voltage --protective' device comprising a condenser be connected across the protected apparatus andmeans connected in parallel to said-condenser for preventing a rise of voltage across the con,-

denser terminals above a value c'orrespond-. ingto the breakdown voltage of the con denser insulation, said means comprising a' gap-devlce and a current limiting-resistor connected 1n'ser1es,-sa1d 'ap device being roportioned to break own below the' reakdown voltage of said c'onde-nseriand to establish a permanent current pathin shunt to said condenser, and meansfor indicating the' flow ofcurrent in said shu-nt path.

metal"'-,discs havingj'a ,layer of varnished flee v 5. 'In combination with a condenser, a 'protect ve device comprising a plurality of silk therebetween' and a resistance elenient in series therewith, said discs and. resistance element beingshunt-connected across said condenser.- E

. In a protective device, a container hav-- ing a condencer dis osed therein and con"- nectedto' terminals t ereon' and a protective device consistingot a film :cutout and a re- -s1s tance element, sa d. cutout and-resistance be ng shuntrconnected across said tc'arminals;

L 7;, Ina protective device,-"a containefhaving a condenser disposed therein-gan'd connected to terminals thereon, aging-having insulatingmaterial therebetweeu, a pair of spring clips, said plug being :heldbetween said-clips, and a resistance element making contact, with one of said-clips',--said element inga'vcou enser disposed therein and connectedptoterminals thereon, a renewable.

,a'stripof and fag being connected across said fteri 8.. In a] rotective device,a'containerihaving contact with one of said clips and said element and plug being connected across said terminals.

9. In a protective device, a container hav- 5 ing a condenser disposed therein and connected to terminals thereon,

' plug having a plurality of metal discs and astrip of varnished silk therebetween, a

pair of spring clips, said plug being held a renewablebetween said clips, a resistance element mak- 1 ing contact with one of said clips and an electric-light bulb connected across :1 or

'tion of said element, said element and plug being connected across said terminals.

In testimony whereof, I have hereunto subscribed my name this 31st day of March,

RALPH E. MALRBURY. 

